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Concept

Sigma model

Related publications (19)

Role of stochastic noise and generalization error in the time propagation of neural-network quantum states

Giuseppe Carleo

Neural-network quantum states (NQS) have been shown to be a suitable variational ansatz to simulate out-of-equilibrium dynamics in two-dimensional systems using timedependent variational Monte Carlo (t-VMC). In particular, stable and accurate time propagat ...

SCIPOST FOUNDATION2022

From SU(2)5 to SU(2)3 Wess-Zumino-Witten transitions in a frustrated spin-52 chain

Frédéric Mila, Natalia Chepiga

We investigate the properties of a frustrated spin-5/2 chain with next-nearest-neighbor two- and three-site interactions, with two questions in mind: the nature of the transition into the dimerized phase induced by the three-site interaction, and the possi ...

2022

Single Skyrmion Generation via a Vertical Nanocontact in a 2D Magnet-Based Heterostructure

Klaus Kern, Marko Burghard, Lukas Powalla

Skyrmions have been well studied in chiral magnets and magnetic thin films due to their potential application in practical devices. Recently, monochiral skyrmions have been observed in twodimensional van der Waals magnets. Their atomically flat surfaces an ...

AMER CHEMICAL SOC2022

Continuous dissipative phase transitions with or without symmetry breaking

Fabrizio Minganti

The paradigm of second-order phase transitions (PTs) induced by spontaneous symmetry breaking (SSB) in thermal and quantum systems is a pillar of modern physics that has been fruitfully applied to out-of-equilibrium open quantum systems. Dissipative phase ...

IOP Publishing Ltd2021

Probing the topology of the quantum analog of a classical skyrmion

Frédéric Mila, Jeanne Colbois

In magnetism, skyrmions correspond to classical three-dimensional spin textures characterized by a topological invariant that keeps track of the winding of the magnetization in real space, a property that cannot be easily generalized to the quantum case si ...

2021

Linearized supergravity with a dynamical preferred frame

Sergey Sibiryakov

We study supersymmetric extension of the Einstein-aether gravitational model where local Lorentz invariance is broken down to the subgroup of spatial rotations by a vacuum expectation value of a timelike vector field called aether. Embedding aether into a ...

Springer Nature2021

Simultaneous autoregressive models for spatial extremes

Emeric Rolland Georges Thibaud

Motivated by the widespread use of large gridded data sets in the atmospheric sciences, we propose a new model for extremes of areal data that is inspired by the simultaneous autoregressive (SAR) model in classical spatial statistics. Our extreme SAR model ...

WILEY2020

Metastable skyrmion lattices governed by magnetic disorder and anisotropy in beta-Mn-type chiral magnets

Henrik Moodysson Rønnow, Jonathan White

Magnetic skyrmions are vortexlike topological spin textures often observed in structurally chiral magnets with Dzyaloshinskii-Moriya interaction. Among them, Co-Zn-Mn alloys with a beta-Mn-type chiral structure host skyrmions above room temperature. In thi ...

AMER PHYSICAL SOC2020

Walking, Weak first-order transitions, and Complex CFTs II. Two-dimensional Potts model at Q > 4

Bernardo Zan, Victor Gorbenko

We study complex CFTs describing fixed points of the two-dimensional Q-state Potts model with Q > 4. Their existence is closely related to the weak first-order phase transition and the "walking" renormalization group (RG) behavior present in the real Potts ...

2018

Spectral properties of a symmetric three-dimensional quantum dot with a pair of identical attractive delta-impurities symmetrically situated around the origin

In this presentation, we wish to provide an overview of the spectral features for the self-adjoint Hamiltonian of the three-dimensional isotropic harmonic oscillator perturbed by either a single attractive delta-interaction centered at the origin or by a p ...

St Petersburg Natl Research Univ Information Technologies, Mech & Optics2016

Prediction of phase ambiguity resolution based on signal intensity and geometry

Jan Skaloud

The goal of this contribution was to develop a reliable quality indicator reflecting the potential success of differential carrier phase ambiguity resolution for kinematic Global Positioning System (GPS). The indicator must be operable without any communic ...

Springer Verlag2015

A mean field model of dynamic and post-dynamic recrystallization predicting kinetics, grain size and flow stress

Roland Logé, Ke Huang

A physically-based two-site mean field model has been developed to describe the microstructural evolution due to recrystallization during and after deformation. The model has been applied to predict the recrystallized fraction, recrystallized grain size, a ...

Elsevier2015

Impact of axions on confinement in three and two dimensions

In this paper we discuss well-known three- and two-dimensional models with confinement, namely, the Polyakov compact electrodynamics in 3D and two-dimensional CP(N-1) sigma model, and reveal changes in the confining regimes of these models upon adding the ...

American Physical Society2015

Ultraviolet completion without symmetry restoration

Solomon G Shamsuddin Osman Endlich

We show that it is not possible to UV complete certain low-energy effective theories with spontaneously broken spacetime symmetries by embedding them into linear sigma models, that is, by adding "radial" modes and restoring the broken symmetries. When such ...

American Physical Society2014

Multipass forging of Inconel 718 in the delta-Supersolvus domain: assessing and modeling microstructure evolution

Roland Logé

This work is focused on the evolution of the microstructure of Inconel 718 during multi-pass forging processes. During the forming process, the material is subjected to several physical phenomena such as work-hardening, recovery, recrystallization and grai ...

E D P Sciences2014

Resting-State Functional Connectivity Emerges from Structurally and Dynamically Shaped Slow Linear Fluctuations

Patric Hagmann

Brain fluctuations at rest are not random but are structured in spatial patterns of correlated activity across different brain areas. The question of how resting-state functional connectivity (FC) emerges from the brain's anatomical connections has motivat ...

Society for Neuroscience2013

Descent properties of hermitian Witt groups in inseparable extensions

Eva Bayer Fluckiger, Daniel Arnold Moldovan

Let k be a field of characteristic ≠2, A be a central simple algebra with involution σ over k and W(A,σ) be the associated Witt group of hermitian forms. We prove that for all purely inseparable extensions L of k, the canonical map rL/k:W(A,σ)⟶W(AL,σL) is ...

Springer Verlag2011

Implications Of Scale Relativity In Gravitational And Electromagnetic Field Theory

Maria-Alexandra Paun

A non-differentiable mechanical model (an alternative to Nottale's Scale Relativity Theory) considering that the particles movements takes place on Peano fractal curves is built. A Navier-Stokes type equation with an imaginary viscosity coefficient for a c ...

2010

Dyson-Maleev representation of nonlinear sigma models

Dmitri Ivanov

For nonlinear sigma models in the unitary symmetry class, the nonlinear target space can be parameterized with cubic polynomials. This choice of coordinates has been known previously as the Dyson-Maleev parameterization for spin systems, and we show that i ...

2008